DE102004017496A1 - Starting device for an internal combustion engine - Google Patents

Abstract

An internal combustion engine startup device (102) predicts whether a starter (104) is required to assist a crankshaft (102b) of the engine (102) before fuel is ignited in a cylinder on an expansion stroke and starts the starter (104). before ignition of the fuel in a cylinder on an expansion stroke, if it is decided that the starter (104) is required.

Description

The The present invention relates to a starting device for an internal combustion engine. Especially The present invention relates to a decision of whether the internal combustion engine with a support using a Starters should be provided.

A common cylinder injection internal combustion engine (hereinafter "engine") has cylinders with Combustion chambers. To start the dormant engine will be fuel injected into the combustion chamber of a cylinder in an expansion stroke (hereinafter "expansion stroke cylinder") and ignited. Of the Fuel burns and generates combustion energy. The combustion energy is used to obtain the power to start the engine. However, the combustion energy alone is sometimes starting the engine insufficient. Various solutions have been used to solve this Problems proposed.

The Japanese Laid-Open Patent Publication JP-2002-4985 discloses a conventional Starter. In the conventional Technique an expansion stroke cylinder is detected, and fuel becomes injected and ignited in the expansion stroke cylinder when the engine is at rest. Furthermore becomes a motor to assist The cranking process used to reliably power the engine start if the engine due to insufficient combustion energy does not start.

The Japanese Laid-Open Patent Publication JP-2002-39038 and Japanese Patent Laid-Open Publication No. Hei Patent Publication JP-2002-4929 discloses other conventional ones Techniques.

Consequently the fuel becomes more conventional Way injected and ignited in the expansion stroke cylinder, and it is determined if the engine will start correctly, and if the engine will not start then it will become a starter to support the starting process of the engine used. In other words decided if the starter is used after it has been confirmed the engine will not start.

There however, it is decided whether the starter will be used after approved was that the engine will not start, there will be a time delay between a theoretical timing for starting the starter and a real time to start the starter generated. As a result, starts the engine sometimes not.

It It is the object of the present invention, at least the problems in the conventional Technology to solve.

A Starting device according to a Aspect of the present invention is for an internal combustion engine, the fuel in an expansion stroke cylinder ignites a cylinder an expansion stroke on a variety of cylinders of the internal combustion engine for starting the internal combustion engine. The starting device has a prediction unit that predicts a crank condition of the cylinders, if the fuel is ignited in the expansion stroke cylinder; and a determining unit that determines whether a starter for supporting a Movement of the crankshaft based on the predicted condition to start.

One Method according to one Another aspect of the present invention is a method for starting an internal combustion engine that ignites fuel in one Expansion stroke cylinder, which is a cylinder during an expansion stroke from a variety of cylinders of the internal combustion engine to start the Internal combustion engine is. The method involves predicting a crank state of the cylinder, if the fuel in the Expansionshubzylinder ignited becomes; and determining if a starter to support a movement the crankshaft based on the predicted condition start is.

Other Objects, features and advantages of the present invention will become more particularly from the following detailed description of the invention, when together with the attached drawings is read.

1 Fig. 4 is a graph showing how the crank torque of an engine changes over the water temperature in a first embodiment of the present invention;

2 Fig. 4 is a graph showing how the air density changes over the water temperature in the first embodiment;

3 Fig. 16 is a graph showing how the rotational angle of a crankshaft in an expansion stroke cylinder changes at an initial combustion above the water temperature in the first embodiment;

4 describes the factors used for predicting a rotational angle of the crankshaft in the first embodiment;

5 describes the factors from those Factors can be obtained which are detected in the first embodiment;

6 Fig. 14 is a graph showing how, at a respective stop position B, a side of TDC at B and a BTDC side of B of the rotational angle of a crankshaft change over the water temperature in the first embodiment;

7 FIG. 12 is a flowchart of a process procedure performed by a starting apparatus according to the first embodiment; FIG.

8th describes a start timing of a starter in a second embodiment of the present invention;

9 describes a transient change in electrical current passing through the starter when coupled to the engine;

10 Fig. 12 is a graph showing various behaviors of a starting current and a rotation of the crankshaft at the starting time in a third embodiment of the present invention and in the conventional art; and

11 shows a functional block diagram of a starting device 110 according to a seventh embodiment of the present invention.

exemplary embodiments a starting device according to the present The invention will be described below with reference to the accompanying drawings described in detail. The present invention is not on the following embodiments limited.

The The present invention relates to operation of a cylinder direct injection gasoline engine (hereinafter "engine") by direct injecting fuel into cylinders of the engine and through Ignite of the fuel by generating a spark. The engine is started in the following way. When the engine rests, then a stop position (or a rotational angle position) a crankshaft (or a crank device) in the respective Cylinder detected to decide if the cylinder is an expansion stroke cylinder is and the fuel is injected into the expansion stroke cylinder and the fuel is ignited, after a predetermined evaporation period has elapsed. Below is Fuel injected into a cylinder (hereinafter "slave cylinder"), the the expansion stroke cylinder follows, and the fuel is ignited when a piston of the slave cylinder top dead center (hereinafter "TDC") at a compression stroke at the initial Combustion in the expansion stroke cylinder exceeds. Below is the fuel in those cylinders ignited one after another, the follow the follower cylinder. This process causes the ignition of the Fuel in the cylinders in succession and starting the engine.

at a first embodiment The present invention is prior to the start of the engine a crank amount of the crankshaft due to combustion of the fuel in the expansion stroke cylinder (hereinafter, "initial combustion") from a temperature a coolant in the engine (or an air condition in the cylinder or an air density) and the stop position (stop angle) of the crankshaft predicted. If so, too the crank amount is such that the initial combustion becomes insufficient is that the piston of the slave cylinder exceeds the TDC of the compression stroke, then the starter motor is started after the crankshaft a Rotation due to the initial Combustion has started.

The The present invention makes use of the fact that it is used to start the Engine without support by external power is essential that the piston of the slave cylinder exceeds the TDC of the compression stroke at the initial combustion, to cause combustion of the fuel in the slave cylinder (hereinafter "second Combustion ") and to a combustion of the fuel in the subsequent cylinders to effect.

Whether the piston of the follower cylinder will exceed the TDC can be determined from (1) a combustion power and (2) a friction force (or rotational resistance). The inventors of the present invention have obtained the following findings from a series of experiments and hard work. The findings are described below with reference to the 4 described.

(1) combustion performance

The combustion power produced is proportional to the amount of oxygen in the cylinder (see (1) in FIG 4 ). The amount of oxygen in the cylinder depends on (a) an air capacity of the cylinder and (b) an air density in the cylinder. The air capacity of the cylinder depends on the stop position of the crankshaft. The air density in the cylinder can be obtained at a temperature of the coolant (hereinafter "water temperature") in the engine 10. If the water temperature is high, then the air density in the cylinder should be small. At a certain stop position of the crankshaft, the amount of oxygen in the cylinder is directly proportional to the air density in the cylinder, the combustion power is directly proportional to the amount of oxygen in the cylinder and the air density is inversely proportional to the water temperature. In other words, the combustion performance drops as the water temperature rises.

(2) friction force

The frictional force is proportional to (c) a friction due to a viscosity of a lubricating oil in the engine and (d) a compaction work in the follower cylinder (see (2) in FIG 4 ). The friction due to the viscosity of the lubricating oil is mainly troublesome in a valve operating system, and the inventors have found that a specific relationship exists between the friction due to the viscosity and the temperature of the oil in the engine (which is generally equal to the water temperature). The inventors have also found that there is a specific relationship between the compression work in the slave cylinder and the stop position of the crankshaft.

The 1 shows in a graphical representation how the crank torque of the engine changes over the water temperature. The cranking torque required to start the engine is minimal when the water temperature is in a half-warmed condition, namely when the water temperature is about A ° C. The cranking torque required to start the engine is greater when the water temperature is above or below A ° C.

The oil temperature decreases if the water temperature is below A ° C, and increases accordingly the viscosity of the oil (Coefficient of viscosity). If the oil a higher one viscosity has, then practices However, there is a friction, so that increases the crank torque. If the water temperature is below A ° C is, then is thus a larger crank torque required to start the engine.

The viscosity of the oil falls off, when the water temperature is over A ° C rises, leaving a lubricating surface from a fluid phase to a solid phase (oil film break) changes, and thereby increased the friction. If the water temperature is above A ° C, then it is again a larger cranking moment required to start the engine.

The 1 shows a case when the rotational speed of the crankshaft is smaller than that during normal operation (ie, when the engine is operated). Such a condition is met when the engine is at rest or nearly at rest. Since the present invention relates to the starting operation of the engine, that case is covered by the present invention, on which the 1 refers. During normal operation, the speed is so high that an oil film break occurs when the water temperature is above A ° C. A graph showing how engine cranking torque changes above the water temperature during normal operation can be obtained by plotting the curve in FIG 1 is moved horizontally to the right.

Since the present invention relates to the starting operation of an engine, and the engine rotates at start-up more slowly than during normal operation, the graph in FIG 1 to the present invention. When the engine is spinning slowly, the lubricating oil is so hard that it slides between the surfaces of the cylinder and the piston such that an oil film break occurs when the water temperature is about A ° C.

The 2 shows in a graphical representation how the air density in the cylinder changes over the water temperature. The air density is inversely proportional to the water temperature. The amount of oxygen in the air decreases as the air density decreases, and the combustion efficiency decreases as the amount of oxygen in the air decreases. In other words, the combustion efficiency decreases as the water temperature rises above A ° C.

The 3 shows in a graphical representation of experimental results, how the rotation angle of the crankshaft in the expansion stroke cylinder at an initial combustion changes over the water temperature. In other words, the shows 3 based on experimental results, how the rotation angle of the crankshaft (° CA) changes in the expansion stroke cylinder when the water temperature rises due to the initial combustion in the expansion stroke cylinder.

The in the 3 shown characteristic is obtained due to the change in friction, which is with reference to the 1 described and due to the change in combustion performance, which is with reference to the 2 is described.

Data about the Water temperature and the rotation angle of the crankshaft were at respective stop positions the crankshaft won in advance and stored as a picture.

The crankshaft rotation angle data includes combustion performance and friction force data. In other words, it was the data for the rotation angle of the crankshaft, the combustion power and the friction force obtained experimentally. When the engine is to be started, it is determined whether the engine will start without assistance of the starter with reference to the map of the stop position of the crankshaft and the water temperature.

In the experiment, a six-cylinder in-line engine was considered in which crank angles of adjacent cylinders were shifted by 120 ° CA relative to each other. In the 3 A stop position B means an angle of the crankshaft in an expansion stroke cylinder, that is, a stop position of the crankshaft.

The 3 corresponds to the case where a stop position of the expansion stroke cylinder is the stop position B. Consequently, the stop position of the crankshaft of the follower cylinder is (B-120) degrees, which is shifted by 120 degrees with respect to the expansion stroke cylinder. In other words, in order to satisfy the condition that the piston of the follower cylinder exceeds the compression stroke TDC, the rotational angle of the crankshaft in the expansion stroke cylinder must be (120 - B) degrees or greater due to the initial combustion in the expansion stroke cylinder. Whether or not the rotational angle of the crankshaft in the expansion stroke cylinder is (120-B) degrees or greater due to the initial combustion will be described with reference to the figure (FIG. 3 ) certainly. From the figure, it can be derived that the rotational angle of the crankshaft in the expansion stroke cylinder due to the initial combustion is (120-B) degrees or more when the water temperature is between C ° C and D ° C. In other words, if the water temperature is between C ° C and D ° C, then the piston of the follower cylinder should exceed the TDC of the compression stroke.

If the water temperature of the engine is between C ° C and D ° C, then it is determined that the engine without the starter can be started. On the other hand, if the water temperature is lower as C ° C or greater than D ° C is, then It is determined that the starter to support the start of the Engine is required.

Of the 3 It can be seen that the angle of rotation of the crankshaft decreases rapidly when the water temperature is about D ° C. This is because the piston of the slave cylinder exceeds the TDC of the compression stroke when the water temperature is about D ° C. When the water temperature is about D ° C, even a small change in the combustion power and the friction force causes a sudden change in the rotational angle of the crankshaft. Therefore, in order to ensure a margin of safety, it may be determined that the starter is not required to assist the engine startup process if the water temperature is a little lower than D ° C.

Consequently is in the first embodiment the stop position of the crankshaft of the follower cylinder from the stop position the crankshaft of the expansion stroke cylinder, and from the obtained stop position, the rotation angle of the crankshaft of Expansion jack obtained with respect to the piston of the Following cylinder is required to the TDC of the compression stroke To exceed (to start the engine without support of external power).

Experiments were carried out with an engine to those in the 3 shown graph in advance, at each stop positions of the crankshaft ( 6 ) on each cylinder, and the data was saved as a map. With reference to the figure, the rotational angle of the crankshaft at the initial combustion in the expansion stroke cylinder can be obtained on the basis of the stop position of the crankshaft for the expansion stroke cylinder and the water temperature. The rotational angle of the crankshaft, that is, a predicted rotational angle of the crankshaft by the initial combustion in the expansion stroke cylinder is obtained by referring to the figure. If the rotational angle of the crankshaft is greater than the rotational angle of the crankshaft required for the piston in the follower cylinder to exceed TDC of the compression stroke, then it is determined that the engine can be started without external assistance.

If in contrast, the predicted angle of rotation of the crankshaft through the initial combustion at the expansion stroke cylinder smaller than the rotation angle of the crankshaft is that for the piston in the follower cylinder to exceed the TDC of the compression stroke is required, then it is determined that the external support to start the engine is required.

at the first embodiment can also be determined before starting the engine, whether the predicted angle of rotation is smaller or larger than the angle of rotation of the Crankshaft is for the piston in the follower cylinder to exceed the TDC of the compression stroke is required so that the starter at an optimal timing can be started.

If the stop positions of the crankshaft, which represents the air capacity of the cylinder, and the compression work in the follower cylinder are equal to each other ( 4 and 5 ), then the rotation Angle of the crankshaft due to the initial combustion by the water temperature, which represents the air density, and are predicted by the oil viscosity. It should be noted that the information in the 5 from the relationship in the 4 have been rewritten, focusing on the stop position of the crankshaft and the water temperature.

If If the stop position of the crankshaft changes, then it changes the amount of compression work in the slave cylinder and the air capacity in the Cylinder, so that the angle of rotation of the crankshaft through the initial Changed combustion becomes.

The 6 FIG. 12 is a graph showing data in cases where the stop positions of the crankshaft are the stop position B, the TDC side of the stop position B and the side before the top dead center (BTDC) of the stop position B. A relationship between the water temperature and the rotational angle of the crankshaft according to the respective stop positions of the crankshaft is measured in advance to prepare an image. The rotational angle of the crankshaft may be predicted based on the water temperature and the stop position of the crankshaft with reference to the figure. It is thereby possible to predict whether the piston of the follower cylinder can exceed the TDC of the compression stroke solely by the initial combustion, based on the predicted rotation angle of the crankshaft.

Like this in the 6 is shown, different stop positions of the crankshaft require different threshold values (water temperature).

Although it is said here that the air density and the oil viscosity are obtained from the water temperature, as in the 4 and the 5 As shown, the air density and the oil viscosity may be obtained by using another parameter or by using other parameters, or they may be obtained by using the water temperature and another parameter (s).

To the Example include the other parameters, for example the duration (hereinafter "holding time") in which the engine is in a stop state. The temperature distribution directly After stopping the engine is tight, as a coolant circulated along a water gallery of the engine, so that the temperature in the cylinder (cylinder temperature) is not strong from the temperature of the coolant (Coolant temperature) which is measured by a temperature sensor. however The cylinder temperature differs due to the heat radiation from the coolant temperature while the holding time. In addition, changes the air density due to the evaporation of remaining fuel while the holding time also over the holding time.

Also when detected by the temperature sensor of the two engines Water temperatures are the same, but are therefore the airtight and the oil viscosities differ, if the holding times differ. To get better results too Therefore, it is preferable that data is measured for each holding time and saved as a picture. On the other hand, the data can be represented by a proportionality constant which depends on the holding time, so as to obtain data which correspond to the holding time.

The 7 shows a flowchart of an operation of the first embodiment. At step S1, it is determined whether a fuel pressure has a predetermined value or more (fuel pressure: residual pressure) on the side of a delivery pipe (fuel passage).

One Pressure is applied to the fuel by an electric pump in the connection injection engines applied. However, it is difficult to get the fuel into a cylinder by injecting the pressure through the electric pump, so that a mechanical pump in direct injection engines (Cylinder Injection Engine) is used. The mechanical Pump is started in response to the engine starting process, to apply the pressure on the fuel. In other words No pressure on the fuel in direct injection engines applied when the engine is at rest.

On the other hand, in the first embodiment, when the engine is stopped for a short time such as idling stop in an oil traveling system, in the first embodiment, it is assumed that the residual pressure remains in the delivery pipe. As described above, when the fuel pressure in the direct injection engine remains, it is possible to supply the fuel by the fuel pressure and to inject the fuel into the expansion stroke cylinder. At the step 1 namely, it is determined whether the residual pressure is present or absent.

If it is determined that the residual pressure is smaller than the predetermined value ("NO" at step S1), then the engine is started exclusively by using the starter, ie, without performing the fuel injection and ignition on the expansion stroke cylinder (step S2). Namely, if the residual pressure in the expansion stroke cylinder is insufficient, it is impossible for the Crankshaft to rotate sufficiently, even if the fuel injection and ignition are performed.

If it is determined that the residual pressure is equal to or greater than the predetermined value is ("Yes" at the step S1), then the system control proceeds to a step S3.

In step S3, the rotational angle of the crankshaft is predicted by the initial combustion in the expansion stroke cylinder based on the water temperature and the stop position of the crankshaft using the map, the data being calculated in accordance with FIG 6 contained therein.

at In a step S4, it is determined whether the water temperature is between E ° C and F ° C is. If the water temperature is too low, d. H. less than E ° C, or if the water temperature is too high, d. H. greater than F ° C, then the crankshaft can not rotate sufficiently, even if the fuel injection and ignition at the expansion stroke cylinder are performed.

If the water temperature is not between E ° C and F ° C ("No" at step S4), then the engine exclusively started using the starter, d. H. without carrying out the Fuel injection and ignition at the expansion stroke cylinder (step S2).

If the water temperature between E ° C and F ° C is ("Yes" at the step S4), then the system control proceeds to a step S5.

The graphic representation in the 3 can be roughly divided into three areas. A first range corresponds to a case where the water temperature is not between E ° C and F ° C. A second range corresponds to a case where the water temperature is between E ° C and F ° C but the rotational angle of the crankshaft is short although the crankshaft is rotated by the initial combustion so as to require assistance of the starter. A third range corresponds to a case where the water temperature is between E ° C and F ° C and the crankshaft rotates until the piston in the follower cylinder exceeds the compression stroke TDC solely by the initial combustion, so that starter assist is not is required.

at a step S5 is predicted whether the piston in the slave cylinder the TDC of the compression stroke exclusively by the initial combustion exceeds in the expansion stroke cylinder. This prediction is based on the angle of rotation of the crankshaft, which is predicted at the step S3, and the rotation angle of Crankshaft performed, the for the piston is required at the follower cylinder, resulting from the stop position of Crankshaft is detected to exceed the TDC of the compression stroke.

If the piston in the follower cylinder the TDC of the compression stroke exclusively by the initial one Combustion at the expansion stroke cylinder may exceed ("Yes" at the step S5), then the engine is exclusive by carrying out the Fuel injection and ignition started at the expansion stroke cylinder, d. H. without using the Starters (step S 7).

If the piston in the follower cylinder the TDC of the compression stroke exclusively by the initial one Combustion in the expansion stroke cylinder can not exceed ("No" at the step S5), then the engine will perform both by Fuel injection and ignition in the expansion stroke cylinder as well as using the starter started (step S 6).

It is possible, too, to measure the speed of the engine in advance by the initial Combustion is caused in the expansion stroke cylinder, and on the changes the speed to this as an illustration in the same way how to prepare the rotation angle of the crankshaft. Therefore, it is possible the Speed and the changes the speed based on the stop position of the crankshaft and predict the water temperature. Such a picture will later as a second embodiment of the present invention.

Consequently Is it possible, to determine if the piston in the slave cylinder is the TDC of the compression stroke through the initial Combustion exceeds, d. H. whether a support the starter is required by the water temperature and the stop position The crankshaft will be detected before the engine starts becomes. This scheme offers the following advantages.

Of the Starter motor generally requires a large electric current for Start, and therefore the starter motor is not directly excited, but a magnetic switch is turned on by a start relay to to excite the starter motor. Consequently, the starter motor at Startup process strongly delayed (Response delay). The delay in the Startup is in the range of about 0.1 to about 0.3 seconds. If it is determined that the starter is required for starting, after the engine has started, and the starter in response On the result of the determination is started, then the optimal Starting time is missing.

at the first embodiment however, it is possible to decide if the starter is required before the engine is started. Therefore, the starter can be started at the optimum timing (the starter is energized) by taking into account the delay time even if the starter has a certain delay in the startup process. Thus, it is possible the startup function by the initial one To improve combustion in the expansion stroke cylinder.

There about that In addition, the angle of rotation of the crankshaft and / or the speed of Engine as well as the changes the speed predicted before the start of the engine, the starter can be started accordingly. Therefore, it is possible, to optimally control the starter.

In addition, if it is determined that the starter is required for starting, then the starter is not activated to start the engine when it is resting, unlike the conventional manner, but it is activated to further accelerate the engine which is already rotating due to the initial combustion in the expansion stroke cylinder. Therefore, the electric power consumption is reduced. This was in the test according to the 10 confirmed, which will be described later.

It has been described above on the basis of both Combustion performance and the frictional force is determined, whether the Piston in the follower cylinder the TDC of the compression stroke through the initial Combustion exceeds. If However, the combustion performance is sufficiently greater, then the determination exclusively on the basis of the size of the combustion power carried out become.

In the first embodiment, the direct injection engine has been described, but the present invention is also applicable to a port injection engine. For cranking the port injection engine, fuel is injected in advance into an intake manifold when the crankshaft is stopped, and in the subsequent step, only one ignition is required to rotate the crankshaft. As described above for starting the port injection engine, the fuel is injected into the intake manifold when the port injection engine is at rest, and an electric pump is used for fuel supply. Therefore, the step of checking the fuel pressure (step S1) in FIG 7 is not performed, but the engine status is predicted based on the water temperature and the stop position of the crankshaft, the water temperature is checked, and it is determined based on the predicted rotation angle of the crankshaft with reference to the figure as to whether the starter needs to be started (steps S 3 to S 5).

The second embodiment of the present invention will be described below with reference to FIGS 8th described.

Of the following operation is based on the operation of the first Embodiment carried out. It namely, will Data (not shown) for the water temperature, the speed of the engine through the initial Combustion in the expansion stroke cylinder and changes the speed in advance at each stop position of the crankshaft won, and the data obtained is stored as a picture.

If It is determined that the starter in the same way in the first embodiment should be started, then a start timing of the starter motor for starting the engine obtained with reference to the figure, prepared in the second embodiment is.

Before The engine is started, the speed of the engine through the initial Combustion in the expansion stroke cylinder and the changes the speed based on the water temperature and the stop position of the Crankshaft predicted with reference to the figure. On the basis of the result of the prediction becomes the operation start timing of the starter motor set so that the starter motor and the engine coupled in a period during which the rotation of the engine through the initial Combustion is accelerated.

It is desirable that the starter motor and the engine are coupled together are when a difference between their speeds is small. This is justified by that noise can be reduced by the coupling between gears of the two and by abrasion of the gears is generated. The startup timing the starter is controlled (sometimes even the speeds are controlled) that the timing of the coupling of the corresponding gears is synchronized, d. H. about the speed of the starter at the same time identical to the speed of the engine or around the engine To reduce the difference between the speeds.

The starter is coupled to the engine while the starter is accelerating. Therefore, it is desirable that the engine is also coupled to the starter when the engine is rotated by the initial combustion is accelerated.

The 8th FIG. 12 is a graph showing a transient change in crankshaft speed by the initial combustion in the expansion stroke cylinder and the starter speed. FIG. The speed is plotted on the y-axis and the time is plotted on the x-axis.

The speed of the crankshaft passing through a curve 10 is accelerated by the initial combustion to reach a predetermined speed, and thereafter it drops. The data for the changes in the speed of the crankshaft, passing through the curve 10 is stored in the figure by previous measurements.

Like this in the 8th is shown, a period during which the crankshaft rotational speed is increased is an acceleration period 11 , and a period during which it is reduced is a delay period 12 ,

Dashed lines 13a to 13c (lines 13a to 13c ) in the 8th indicate each speed of the starter motor. The lines 13a to 13c have only at a start timing of the starter motor from each other different points.

As described above, the starter and the engine are desirably coupled with each other when a difference between their rotational speeds is small. Therefore, the crankshaft and the starter are coupled together (gears of the two are coupled together) when the speed of the crankshaft, through the curve 10 is equal to the respective speeds of the starter, which is due to the different lines 13a to 13c are indicated.

After the starter is coupled to the crankshaft, we accelerate the crankshaft through the starter as the speed of the starter is faster. In other words, the speed of the crankshaft changes as a thick line 11a is shown, if the crankshaft is coupled to the starter, which is started at the timing passing through the line 13a is specified. If the crankshaft is similarly coupled to the starter that is started at the timing that passes through the line 13b is specified, then the speed of the crankshaft changes, as by a thick line 11b is specified. In addition, if the crankshaft is coupled to the starter that is started at the timing that passes through the line 13c is specified, then the speed of the crankshaft changes, as by a thick line 11c is specified.

If the change (acceleration) in the rotational speed of the crankshaft is smaller before and after the coupling with the starter, then the impact caused by the coupling is weaker, and noise and abrasion caused by the coupling of the gears are less. From the ones through the thick lines 11a to 11c specified changes causes that change caused by the thick line 11a is indicated, the weakest shock, while that change caused by the thick line 11c indicated causes the strongest impact.

The starter is coupled to the engine while the starter is accelerating. Therefore, the starter is desirably coupled to the engine when the rotation of the engine is accelerated by the initial combustion (the acceleration period 11 ), since the impact caused by the coupling is reduced.

As As described above, the timing needs to start the starter according to the timing to start the engine controlled by the initial combustion become. However, a delay When starting the starter to prevent it is necessary to Signal to start the starter to generate before the engine through the initial one Combustion is started. In the conventional technique it is determined whether the support The starter is required after the engine starts has been. Therefore, the starter can not be at the optimal timing to be started.

at a third embodiment The present invention provides an energization time of the starter motor in the first and second embodiments with a minimum amount determined for the piston of a slave cylinder necessary following that cylinder at which the initial combustion carried out becomes (expansion stroke cylinder) to exceed the TDC of the compression stroke. If the piston of the follower cylinder exceeds the TDC of the compression stroke, then there is no need for starter support, and therefore the excitation time is determined accordingly.

When the ignition is performed on the slave cylinder, a new traction is generated, making it possible to stop the starter's assistance. In the example, it is appropriate that the assistance of the starter is maintained only until the crankshaft at the follower cylinder is effected by (120-B) ° and exceeds the TDC of the compression stroke. Therefore, the energization time of the starter motor is set to an amount corresponding to the amount of assistance of the starter. As described above, it is possible to determine whether the Support of the starter should be stopped, based on the position of the crankshaft, namely, whether the crankshaft was rotated by (120-B) °.

The 9 FIG. 12 is a graph showing a transient change in an electric current (starter current) passing through the starter motor when the starter starts the engine when the engine is resting, as conventionally performed. FIG.

Like this in the 9 is shown, the coupling of the starter with the engine causes a delay of the starter motor, and thereby the starter current drops suddenly and increases slightly immediately after the waste (area P).

To the coupling with the engine vibrates the starter current several times vertical like a wave. When the starter current is increased, then this means that the engine is in the compression stroke is, so the load increases becomes (area Q). As the starter current decreases, it means that the piston exceeds the TDC of the compression stroke, so that the Load reduced (range R). In the area R is the engine in the expansion stroke, and the engine is powered by the combustion power accelerated so that it is once decoupled from the starter, and accordingly the gears are decoupled.

In a region S in which the starter current to the low level has decreased and begins to increase again, the engine enters in the compression stroke, so that the engine speed reduced. As a result, the engine is again with the Starter coupled.

In the third embodiment, the fuel injection and ignition are performed on the expansion stroke cylinder to start the rotation of the crankshaft, and the starter is coupled to the crankshaft while the starter is accelerated. This point differs from the conventional method for coupling the starter to the crankshaft when it is at rest and for starting the rotation of the crankshaft. Like this in the 9 however, the transient change of the starter current after the starter device has been coupled to the engine (the curve after the region P) is the same as in the third embodiment.

As described above, the energization time of the starter motor is set so that the assist of the starter is performed until the piston in the follower cylinder exceeds the TDC of the compression stroke, but it is not performed after the piston has exceeded the TDC. Therefore, in the third embodiment, the energization of the starter may be stopped at a time point T1 when the electric current exceeds a peak value of the current in the region Q indicating that the piston is making the TDC of the compression stroke according to FIG 9 exceeds. As described above, it is possible to determine when to stop the assist of the starter based on the transient change of the starter current.

The 10 shows a graphical representation of behavior of the starter current and the rotation of the crankshaft during the starting process of the engine.

The reference number 21 denotes a transient change of the rotational angle of the crankshaft in the third embodiment, and the reference numeral 22 denotes a transient change in the rotation angle of the conventional crankshaft. The reference number 22 denotes a transient change of currents of the starter current in the third embodiment, and the reference numeral 24 denotes transient changes of currents of the starter current in the conventional art.

Conventionally, the starter device causes rotation of the crankshaft to start when it is resting (point 22a ) after the current has started to flow through the starter (point 22s ). The rising edge at the point 22a agrees with the time of a peak 24a a line 24 match. This indicates that the gears are coupled together to cause rotation of the crankshaft to start. At this time, a large current temporarily passes through the starter. An area 24b indicates that the load is so great that the piston exceeds the TDC of the compression stroke and an area 24c indicates that the load is small due to the expansion stroke. An area 24d indicates that the load is high due to a next compression stroke.

In the third embodiment, the flow of current through the starter (point 23s ) at the time when the crankshaft starts its rotation (point 21a ), and the acceleration has started. It should be noted that the magnitude of the current that begins to flow through the starter is the same as in the conventional technique (dots 22s and 23s ).

Since the starter is coupled to the crankshaft, which is accelerated during acceleration of the starting device, the load applied to the starter during the coupling is at all not big. This prevents the flow of excessive current through the starter.

One point 23e indicates a point in time when the starter is stopped. Before the point 23e there is a portion indicating that the load increases in the compression stroke, and that the current increases and then the TDC of the compression stroke is exceeded, and that the load decreases and a decrease of the current begins. The point 23e is a time when a decrease in the starter current begins. As described above, it is determined whether the assist of the starter is stopped on the basis of the transient change of the starter current.

In the third embodiment, the starter is coupled to the crankshaft which is accelerated during the acceleration of the starter, and therefore, the timing at which the piston exceeds the TDC is earlier (point 23e and area 24b ) than in the conventional method. Under the same condition, the excitation time of the conventional starter is slightly shorter than one second, while the excitation time of the starter in the third embodiment is α seconds (FIG. 23e ) can be suppressed.

As As described above, there are two methods of the method for determining the stopping operation based on the position of the crankshaft and the method for determining the stop operation based on the change the amperage, which passes through the starter. In addition, the excitation time set as a predetermined time after the start of the starter being taken into account will slow down the starting process of the starter when it is at rest. In other words, first of all detects that the crankshaft is positioned at a predetermined angle (120-B) ° is, and then the starter is stopped when based on The position of the crankshaft determines that the starter stopped shall be. It should be noted that the starter after a delay time the boot process actually is stopped, which elapses after that time, when a stop signal is sent to the starter. In this method, an actual Excitation time sometimes exceed the required minimum time.

Therefore the angle of rotation of the crankshaft becomes de energizing time the starter measured in advance to the results of the measurement as a To get picture. In the example, in other words, one Excitation time of the starter from the figure obtained to the rotation angle of the crankshaft at (120-B) °. Therefore, it is by exciting the starter only during this time possible, the excitation time to the required minimum without an influence the delay to suppress during the boot process.

According to the third embodiment Is it possible, the excitation time of the starter for a required minimum time reduce and reduce power consumption.

If the combustion in the slave cylinder has an error or if the combustion power of combustion in the slave cylinder not appropriate, then no combustion in the cylinder take place after that, and as a result it is sometimes impossible to do so Start engine.

at a fourth embodiment According to the present invention, the starter motor is started when using the technique of the first to third embodiments it is determined that the piston in a cylinder (hereinafter "third cylinder"), the follower cylinder The TDC of the compression stroke does not exceed that after the piston in the slave cylinder, the cylinder with the initial Combustion follows, the TDC of the compression stroke has exceeded.

Concrete it is determined whether the piston in the third cylinder is the TDC of the Exceeds compression strokes, by the rotational speed or the speed of the engine or the spin of the engine is detected.

Two Cases can be considered before the starter motor is started, the third Cylinder exceeds the TDC of the compression stroke. In a case exceeds the piston in the slave cylinder, the cylinder with the initial combustion follows the TDC of the compression stroke exclusively through the initial one Combustion without starting the starter. In a second case exceeds the piston in the slave cylinder through the TDC of the compression stroke support the initial one Burning by the starter.

at the fourth embodiment The excitement of the starter is stopped once when the piston of the slave cylinder has exceeded the TDC of the compression stroke, as this described in particular in the third embodiment is. If, however, it is determined thereafter that the piston of the third Cylinder does not exceed the TDC of the compression stroke, then the Starter motor started again.

According to the fourth Embodiment may the engine will be started even if no combustion occurs in the slave cylinder or if the combustion power is not appropriate.

According to the fourth Embodiment may about that In addition, the excitation time of the starter is reduced to a minimum time which allows a reduction in power consumption, if this with the conventional Starting procedure is compared, in which the starter continues to excite until the boot process is complete.

at the fourth embodiment becomes the starter motor for the third cylinder during a rotation of the crankshaft started, and the excitation time of Starter motor is considered a required amount for the piston in the third cylinder to exceed determined by the TDC of the compression stroke. In a fifth embodiment The present invention will be described in the same way as in the third embodiment realized.

The fifth embodiment The present invention has the advantages described below.

It a smaller power is consumed because the starting direction with the is coupled to a rotating engine.

It becomes a weaker one Shock caused, if the gears be coupled with each other, and therefore both noise and Abrasion kept at a low level.

It is a reduction in power consumption possible because the excitation time of the starter can be reduced to a minimum.

at a sixth embodiment the present invention, the respective operation of the fourth and the fifth embodiment carried out, until the engine without support from external power can be operated by yourself. In a sixth embodiment According to the present invention, the determination is carried out by the Rotational speed or the speed of the engine or the Spin of the engine is detected.

The sixth embodiment The present invention has the advantages described below.

The Engine can be started even if no combustion takes place in the third cylinder and the subsequent cylinders.

The The excitation time of the starter is reduced to a minimum, which is a allows reduced power consumption, if this with the conventional Starting method is compared, in which the starter remains energized, until the boot process is completed.

The 11 shows a functional block diagram of a starting device 110 according to a seventh embodiment of the present invention. The starting device 110 has a prediction unit 100 , a determination unit 105 , a starter control device 103 , a starter 104 and a storage unit 105 , The starting device 110 controls an engine 102 , The engine 102 has a variety of cylinders 102 and a crankshaft 102b which moves pistons (not shown) inside the cylinders. Various types of sensors (not shown) measure a variety of physical characteristics of the engine. For example, a temperature sensor (not shown) measures a temperature of the water in the engine.

The storage unit 105 stores the above-mentioned many pictures. The prediction unit 100 says a condition of the crankshaft 102b based on a variety of parameters (for example, the crankshaft position and the water temperature) and the figures in the memory unit 105 are stored. The determination unit determines whether the engine 102 start directly by the combustion power, or whether the starter 104 to start the engine 102 is required. If the starter is required then the destination unit will send 101 a signal (not shown) to the starter control device 103 , The starter control device 103 sees a control to start the starter 104 in front.

According to the starting device for the Internal combustion engine according to the present invention Invention, the starter is started at an optimal timing, which enables an improvement of the starting power for ignition, the expansion stroke cylinder supplied becomes.

Also when the invention in terms of a specific embodiment to the full and clear disclosure, the appended claims are not limited to but you can To cover modifications and alternative constructions that a professional recognizes from the technical teaching presented here.

A starting device for an internal combustion engine ( 102 ) predicts whether a starter ( 104 ) a crankshaft ( 102b ) of the engine ( 102 ) before fuel is ignited into a cylinder on an expansion stroke and it starts the starter ( 104 ) before ignition of the fuel in a cylinder in an expansion stroke, if it is decided that the starter ( 104 ) is required.

Claims (20)

Starting device for an internal combustion engine ( 102 ), which ignites fuel in an expansion stroke cylinder, which is a cylinder in an expansion stroke of a plurality of cylinders ( 102 ) of the internal combustion engine ( 102 ) is to the internal combustion engine ( 102 ), with: a prediction unit ( 100 ), which is a state of a crankshaft ( 102b ) the cylinder ( 102 ) predicts when the fuel is ignited in the expansion stroke cylinder; and a determination unit ( 101 ) which determines on the basis of the predicted state whether a starter ( 104 ) for supporting a movement of the crankshaft ( 102b ) is to start. Starting device according to claim 1, wherein the prediction unit ( 100 ) a state of the crankshaft ( 102b ) is predicted before a first ignition is performed in the expansion stroke cylinder, and the determination unit ( 101 ) determines whether the starter ( 104 ) before the first ignition is performed in the expansion stroke cylinder. Starting device according to claim 1 or 2, wherein the prediction unit ( 100 ) the condition of the crankshaft ( 102b ) based on a stop position of the crankshaft ( 102b ) and a water temperature in the internal combustion engine ( 102 ) appreciates. Starting device according to one of claims 1 to 3, wherein the prediction unit ( 100 ) estimates a combustion power which is generated when the fuel is ignited in the expansion stroke cylinder and the state of the crankshaft (FIG. 102b ) is predicted based on the estimated combustion performance. Starting device according to claim 4, wherein the prediction unit ( 100 ) estimates an amount of oxygen in the expansion stroke cylinder and estimates the combustion performance based on the estimated amount of oxygen. Starting device according to claim 5, wherein the prediction unit ( 100 ) the amount of oxygen based on a stop position of the crankshaft ( 102b ) according to an air capacity in the expansion stroke cylinder. Starting device according to claim 5 or 6, wherein the prediction unit ( 100 ) estimates an air density in the expansion stroke cylinder and estimates the amount of oxygen based on the estimated air density. Starting device according to claim 7, wherein the prediction unit ( 100 ) the air density based on the water temperature in the internal combustion engine ( 102 ) appreciates. Starting device according to one of claims 4 to 8, wherein the prediction unit ( 100 ) estimates a frictional force generated when the fuel in the expansion stroke cylinder is ignited and the state of the crankshaft (FIG. 102b ) is predicted based on the estimated friction force as well as the estimated combustion power. Starting device according to claim 9, wherein the prediction unit ( 100 ) estimates the frictional force based on the friction generated when the crankshaft ( 102b ), and based on a compaction work in a slave cylinder following the expansion stroke cylinder. Starting device according to claim 10, wherein the prediction unit ( 100 ) the frictional force based on the stop position of the crankshaft ( 102b ) which corresponds to the compaction work in the slave cylinder. Starting device according to claim 10 or 11, wherein the prediction unit ( 100 ) estimates an oil viscosity according to the friction and estimates the friction force based on the estimated oil viscosity. Starting device according to claim 12, wherein the prediction unit ( 100 ) the oil viscosity on the basis of the water temperature in the internal combustion engine ( 102 ) appreciates. Starting device according to one of claims 1 to 13, wherein the state of the crankshaft ( 102b ) either a rotational angle of the crankshaft ( 102b ) or a speed of the internal combustion engine ( 102 ). Starting device according to one of claims 1 to 14, further comprising a starter control device ( 103 ), the starter ( 104 ) when picking up a trigger signal from the determination unit ( 101 ), when the determination unit ( 101 ) determines that the starter ( 104 ), wherein the starter control device ( 103 ) a controller for starting the starter ( 104 ) after the fuel is ignited in the expansion stroke cylinder. Starting device according to one of claims 1 to 15, further comprising a starter control device ( 103 ), the starter ( 104 ) when picking up a trigger signal from the determination unit ( 101 ), when the determination unit ( 101 ) determines that the starter ( 104 ), wherein the starter control device ( 103 ) a controller to start the starter ( 104 ) at a timing such that the starter ( 104 ) and the internal combustion engine ( 102 ) are coupled together when the crankshaft ( 102b ) is in an acceleration state. Starting device according to one of claims 1 to 16, further comprising a starter control device ( 103 ), the starter ( 104 ) when picking up a trigger signal from the determination unit ( 101 ), when the determination unit ( 101 ) determines that the starter ( 104 ), wherein the starter control device ( 103 ) a controller for supplying a current to the starter ( 104 ) such that the supplied flow has a minimum size required for a piston in a slave cylinder following the expansion stroke cylinder to exceed a top dead center of a compression stroke. Starting device according to one of claims 1 to 17, further comprising a starter control device ( 103 ), the starter ( 104 ) when picking up a trigger signal from the determination unit ( 101 ), when the determination unit ( 101 ) determines that the starter ( 104 ), wherein the starter control device ( 103 ) a controller for starting the starter ( 104 ) at a timing such that when the starter ( 104 ) is started and stopped after a certain time, but is started a second time, since it is determined that the rotational state of the crankshaft ( 102b ) the starter ( 104 ), a start time is set the second time so that the starter ( 104 ) during a rotation of the crankshaft ( 102b ) with the internal combustion engine ( 102 ) is coupled. Method for starting an internal combustion engine, that's an ignition of fuel in an expansion stroke cylinder having a Cylinder in an expansion stroke of a plurality of cylinders of the internal combustion engine is to start the engine with: predict a state of a crankshaft of the cylinder when the fuel ignited in the expansion stroke cylinder becomes; and Determine if a starter to support a movement The crankshaft is to start, based on the predicted State. Method according to claim 19, where the forecasting is done before a first ignition in the expansion stroke cylinder is performed, and the determining carried out will be before the first ignition is performed in the expansion stroke cylinder.